Cold Chain Strategies That Beat the Summer Heat

It takes a village to raise our children, we’re told. But that’s nothing compared to what it takes to deliver the goods for a summer party serving refreshing delectables.

Behind every ice cream social, guacamole get-together, and surf ‘n’ turf soiree, an international network of researchers, regulators, IT specialists, drivers, warehouse workers, and supply chain professionals toil to power the cold chain—the network of refrigerated transportation, storage, and distribution functions that keeps the chill on for thousands of food products. As they journey from the point of harvest to the party buffet table, these prima donna products require refrigerated surroundings and gentle handling.

"Every food you eat takes a unique journey," says Corey Rosenbusch, president and CEO of the Global Cold Chain Alliance (GCCA). "It starts somewhere on the field, on the farm, or in the ocean, and there are many nodes along the way."

Every supply chain has its complexities, he acknowledges, but the cold chain adds temperature sensitivity, limited shelf life, and seasonality to the already challenging mix. Here’s a taste of some cold chain strategies that bring sizzle to summer parties.

On the Road With the Delicate Avocado

Bringing the thick-skinned avocado to market is no easy feat. Even plucking the stone fruit is a matter of carefully calibrated strategic timing. After all, says the California Avocado Commission, avocados ripen only once they are mature and only after they are picked—and then they can’t wait to decay.

To ensure they travel at the desired state between ready to ripen and rotten, Golden State avocados leave the packing plant only after they are subjected to an ethylene gas treatment. This regulates the ripening of fleshy fruits and helps forestall the discoloration associated with aging.

En route to the distribution center or grocery store, avocados—whether originating in Mexico or Australia, and traveling by land or sea—typically prefer a container cooled to a brisk 1 degree Celsius. A mere 4-degree boost in temperature can shrink the stone fruit, and shrinking means a less desirable product. As a result, avocados are monitored closely during shipment for variations in light exposure and temperature. If any fluctuation is detected, a troubleshooting team can intervene promptly to minimize damage and ensure the product’s integrity.

If avocados like to hang out at just above freezing temperatures, other fruits beg to differ. When it comes to maintaining product safety and quality, Rosenbusch explains, no two items seem to share the same requirements. That’s why the cold chain has rules and regulations spelling out the proper temperatures and handling protocols for more than 200 fresh foods.

Fruits of Labor

Like other wards of the cold chain, the berries and fruits that make up a tangy summer salad must be handled gently and monitored relentlessly as they progress from Point A to market. That’s because a bruising ride across the country or a failure to maintain temperature consistency along the chain can compromise product quality and safety, says Douglas Harrison, president and CEO of Ontario-based VersaCold Logistics Services. As chairman of the International Association for Refrigerated Warehouses, a core partner association of the GCCA, he’s tuned to the needs of everything from the tiniest kumquat to the heftiest melon.

Speed is of the essence with fresh fruits, which need to be cooled to their minimum safe temperature almost immediately after harvest. It’s essential to reduce the so-called "heat load" that has built after extended periods in the sun. Rapid cooling, perhaps enlisting chilled water or forced air, helps ensure the biochemical processes associated with ripening and rotting are slowed, if not arrested.

From there, "all these products require a great deal of sensitivity around temperature bands and times of delivery," Harrison explains. Every link of the chain, even the simple transfer from one vehicle to another, has to be planned and coordinated.

"When a product has to be offloaded from one truck onto another truck, every one of those facilities must be temperature controlled," he adds.

Before being routed to its final destination, the grocery store, a lot of produce is staged at a distribution center. There, it’s sorted—gently—into pint-sized ventilated containers or perhaps diced, chopped, and bagged. The temperatures during this process occasionally fall above or below the optimum for individual products, but warehouse workers move quickly to assure that no product spends too much time in suboptimal conditions.

With a limited shelf life of perhaps four or five days, these products need to sell quickly. Coordinating just-in-time deliveries of products that decay at inconvenient rates requires strategic planning. That puts predictive analytics to work optimizing the supply chain, and is where data comes in, says Toby Brzoznowski, the chief strategy officer for software design company LLamasoft.

In the cold chain, keeping waste down, profits up, and prices low requires ongoing analysis of what Brzoznowski calls the most influential causal variables—everything from the Consumer Price Index to a product’s sales history. With the right information in hand, producers can ascertain and maximize their capacity to manufacture, ship, and warehouse.

If, say, huckleberries only do well in flush times, farmers can restrain production, fine tune processing, and restructure the warehouse should an economic slump loom.

The human brain struggles to convert temperatures from Fahrenheit to Celsius. Analyzing the bushels and pecks of raw data needed for careful planning is nearly impossible. "Millions of combinations, with seasonality factored in, is too much to calculate in a spreadsheet," Brzoznowski says.

Shrimp: A Jumbo Challenge

On menus, shrimp cocktail is often billed as an appetizer, but for many partygoers, it’s the rock star of the show.

In the United States, most of the shrimp consumed domestically is imported. Some of it crosses into the country at the Arizona ports of Nogales and Tucson, where the desert’s extreme heat makes keeping a cold chain intact an enormous challenge.

The challenge is intensified when the shrimp, snug in their shrink wrap, have to be transferred from a refrigerated truck to a refrigerated rail car—a shift in conveyance made necessary by the long distances associated with a Tucson-to-Next Stop journey. Even the coolest desert day presents plenty of opportunity for the product to thaw.

Enter the mobile crossdock. It’s a solution employed for hundreds of products that can’t take the heat. Union Pacific uses the crossdock to ensure shrimp coming from Mexico make it to their U.S. destinations in shipshape.

Think of the mobile crossdock as a temperature-controlled shed that stands at the same height as a rail car and refrigerated trailer. Once it is cooled to just the right temperature and positioned between the two reefers, a door on each side opens, allowing the crossdock to serve as a chilled bridge. The shrimp can then be transferred without ever seeing so much as a ray of unfiltered sun.

Thanks to strategies like these, shrimp arrive at their final destination ready to be dipped in cocktail sauce or butter.

Prime Cuts Meat With Success

For beef and poultry products, the cold chain kicks in, pronto, at the point of harvest.

Most meat carcasses undergo a primary and secondary chilling, according to a November 2017 article in Poultry Reporter. With the primary chilling, the carcasses should reach the desired temperatures, which vary according to the animal in question, in as few as two hours from slaughter. The meat is kept cold enough to ward off microbial growth, but not so cold as to make deboning and fileting too difficult.

The second chilling comes when the meat is separated from the bone and minced or sliced into select cuts. This done, the meat is either air chilled, immersion chilled, spray chilled, or vacuum chilled. It is then loaded into a refrigerated truck, calibrated to the desired temperature, and dispatched to a distribution center or marketplace.

At the warehouse, receivers verify temperature integrity and log the manufacturing date. Like dairy and any other items likely to spoil, the product will then be stored according to a FEFO strategy, a variation on the FIFO warehousing practice of "first in, first out." For products with limited shelf life, FEFO ensures that, regardless of arrival date, the first expired are the first out the door.

"On short-term products, this is critical," says John Haggerty, vice president of business development at family-owned and operated Burris Logistics.

The Scoop on Ice Cream

Some cold chain products are meant to melt in the mouth—and not a moment sooner.

That’s the expectation for ice cream, a beat-the-heat scene stealer whose cold chain begins with an array of inbound raw materials, everything from berries and nuts to peanut butter and chocolate. Like the final product, "each part has its own unique temperature and handling requirements," Harrison says.

Once the ice cream is blended, transporting and warehousing it are particularly challenging, because even the tiniest fluctuation in temperature can affect the product’s texture. No consumer wants to bring home a product scarred by freezer burn.

Just as important, says Haggerty, ice cream requires a certain distance from other cold-chain products—bacon or salmon, for instance. "Butter fat can take on other flavors," he says, adding that for this product, a segregated cold chain is essential.

So is a time-sensitive and efficient supply chain. Deliveries must be scheduled precisely, Haggerty cautions. Arriving dockside with gallons of sorbet at break time is cold-chain malpractice. With products like these, there is no time for heel cooling. Even at refrigerated docks, where the temperature typically ranges from 36 to 38 degrees Fahrenheit, frozen foods need to be rushed to their preferred habitats.

The Last Link: A Cold, Hard Fact

Thanks to robust monitoring and state-of-the-art refrigeration, 99.9-plus percent of all temperature-sensitive items skate through the cold chain in tip-top shape.

They’re safe, beautiful, and ready for their taste test.

Until, that is, they’ve been purchased. When consumers leave the store, heave their market bags into the car’s suffocating trunk, and begin the journey home, the chain breaks down.

And that’s where Harrison of the International Association for Refrigerated Warehouses averts his eyes: "That," he sighs, "is the greatest point of loss of integrity."